package com.linktco.common.utils;


import io.swagger.annotations.ApiModelProperty;
import lombok.Builder;
import lombok.Data;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import java.util.UUID;

public class AppSecretUtils {

	private final static String[] chars = new String[]{"a", "b", "c", "d", "e", "f",
		"g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s",
		"t", "u", "v", "w", "x", "y", "z", "0", "1", "2", "3", "4", "5",
		"6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "G", "H", "I",
		"J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V",
		"W", "X", "Y", "Z"};



	public static void main(String[] args) {
		AppSecretInfo appInfo = getAppInfo("leliven-park");
		System.out.println(appInfo.getAppId());
		System.out.println(appInfo.getAppSecret());

	}



	/**
	 * 短8位UUID思想其实借鉴微博短域名的生成方式，但是其重复概率过高，而且每次生成4个，需要随即选取一个。
	 * 本算法利用62个可打印字符，通过随机生成32位UUID，由于UUID都为十六进制，所以将UUID分成8组，每4个为一组，然后通过模62操作，结果作为索引取出字符，
	 * 这样重复率大大降低。
	 * 经测试，在生成一千万个数据也没有出现重复，完全满足大部分需求。
	 *
	 * @author zhangnx
	 * @date 2021-12-08 16:16
	 */
	public static String getAppId() {
		StringBuffer shortBuffer = new StringBuffer();
		String uuid = UUID.randomUUID().toString().replace("-", "");
		for (int i = 0; i < 8; i++) {
			String str = uuid.substring(i * 4, i * 4 + 4);
			int x = Integer.parseInt(str, 16);
			shortBuffer.append(chars[x % 0x3E]);
		}
		return shortBuffer.toString();

	}


	public static AppSecretInfo getAppInfo(String serverName) {
		String appId = getAppId();
		String appSecret = getAppSecret(appId, serverName);
		return AppSecretInfo.builder().appId(appId).appSecret(appSecret).build();
	}





	/**
	 * 通过appId和内置关键词生成APP Secret
	 * @param appId
	 * @param serverName
	 * @return
	 * @author zhangnx
	 * @date 2021-12-08 16:32
	 */
	private static String getAppSecret(String appId, String serverName) {
		try {
			String[] array = new String[]{appId, serverName};
			StringBuffer sb = new StringBuffer();
			// 字符串排序
			Arrays.sort(array);

			for (int i = 0; i < array.length; i++) {
				sb.append(array[i]);
			}
			String str = sb.toString();
			MessageDigest md = MessageDigest.getInstance("SHA-1");
			md.update(str.getBytes());
			byte[] digest = md.digest();

			StringBuffer hexStr = new StringBuffer();
			String shaHex;
			for (int i = 0; i < digest.length; i++) {
				shaHex = Integer.toHexString(digest[i] & 0xFF);
				if (shaHex.length() < 2) {
					hexStr.append(0);
				}
				hexStr.append(shaHex);
			}
			return hexStr.toString();
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
			throw new RuntimeException();
		}
	}





	@Data
	@Builder
	 static class AppSecretInfo {
		@ApiModelProperty("appId")
		String appId;

		@ApiModelProperty("appSecret")
		String appSecret;

		@ApiModelProperty("私钥")
		String privateKey;

		@ApiModelProperty("公钥")
		String publicKey;

		@ApiModelProperty("数据是否加密")
		Boolean isDataEncryption;
	}


}



